/*-
 * Copyright (c) 2011 Ondrej Fischer <ondrej.fischer@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#ifndef  EXPRESS_BLOCKINGQUEUE_HPP
#define  EXPRESS_BLOCKINGQUEUE_HPP

#include <queue>
#include "mutex.hpp"


namespace express {

    
    /**
     * Template class BlockingQueue is synchronized queue with the capability
     * to block the item requestor if the queue is empty.
     */
    template<typename TYPE> class BlockingQueue {


    private:

        /**
         * The mutex lock to prevent concurrent modification of the queue
         */
        Mutex::Condition* condition;
        
        /**
         * The queue structure used to store the items
         */
        std::queue<TYPE> _queue;

    
    public:
        
        /**
         * Conscturctor of the blocking queue
         */
        BlockingQueue()
        : _queue(), condition((new Mutex(Mutex::recursive))->condition())
        {}

        /**
         * Get an item from the queue
         */
        TYPE& deq() {
            condition->mutex()->lock();
            while(_queue.empty()) condition->wait();
            TYPE& item = _queue.front();
            _queue.pop();
            condition->mutex()->unlock();
            return item;
        }

        /**
         * Insert item into the queue
         */
        void enq(const TYPE& val) {
            condition->mutex()->lock();
            _queue.push(val);
            condition->signal();
            condition->mutex()->unlock();
        }


    };


};


#endif //EXPRESS_BLOCKINGQUEUE_HPP



